Anybody familiar with this cartridge? Friend just gave me a bag with some misc loaded rounds in it and there were a few of these in the bag.

never heard of it -- and as I bought the tooling, and have the first actual 49 caliber rifle and carts, i'd love to hear about it

Maybe they are going off the the bore and not the groove dimension for a .500" variant.

jeff -Looking at it again I just now considered that maybe the head stamp was a base case that was necked down for some kind of pretty good sized wild-cat. If you send me a shipping address I'll send one out to you.

Ah, me, the eyes ain't what they used to be. I picked up the bag with those "490 Express" cartridges in it to get one out to give to a friend for his collection. In a better light the head-stamp is "470". Time to get the prescription checked.
So anybody shooting a .470 Express and need a few extra rounds? Soft-nose and FMJ.

As a side question, wasn't there are 490 A Square or similar number....sort of like a fat 458 Lott on the 460 Wby case?

495 and 500 a2 -- basically the same case, but the 495 is a tad shorter to not require huge actions

the 500 AccRel is a .510, and the 490 AccRel is a 49 caliber -- a TRUE 49 caliber, as the bore is .490 and the groove is .498 -- and, btw, the 475 AccRel is a .475 ---

all of these on the same case, neck to the .510, .498, and .475 bullet -- a shortened, improved rigby (or derimmed weatherby) case that fits in a standard ruger/win/mauser -- designed around modern powders, with a mission statement to make 2150 with "correct" bullet weights (same used in double rifles of the same or new caliber) -- all of them can greatly exceed that --